Making a Difference: Bridging Theory and Practice

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Making a Difference Bridging Theory and
Practice Philip C. Singer University of
North Carolina at Chapel Hill
Practice
Theory
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Premises There is a theoretical basis for what
happens in practice. If you understand the
theory, you can improve the practice. As
engineers, practical applications drive the
theoretical research that we do.
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How do we develop an appreciation for the
practical applications that define and drive our
research? Read practice-oriented journals, e.g.
WER, JAWWA, JEED, as well as scientific journals.
Visit treatment facilities. Collect and analyze
samples from treatment facilities and receiving
bodies of water and integrate them into classes
and projects. Collect and analyze data from
treatment facilities and regulatory agencies and
integrate them into classes and projects. Become
involved with professional organizations, e.g.
WEF, AWWA, AAEE, EWRI, and serve on
committee. Attend professional conferences.
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Theory
Practice
Examples from my own career Examples from the
careers of others
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• Phil Singer (1)
• Disinfection Byproducts
• In 1974, it was discovered that chlorine applied
  to water forms disinfection by-products (DBPs)
  that may have adverse human health effects.
• Consumption of chlorinated drinking water was
  linked to cancers of the digestive and urinary
  tracts.
• DBPs have been regulated in finished drinking
  water since 1979.

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Babcock, D. B. and P. C. Singer, "Chlorination
and Coagulation of Humic and Fulvic Acids,"
Journ. Amer. Water Works Assn., 71, 149
(1979). Young, J. S. and P. C. Singer,
"Chloroform Formation in Public Water Supplies
A Case Study," Journ. Amer. Water Works Assn.,
71, 87 (1979).
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• Coagulation of DBP Precursors
• Coagulation has been shown to be very effective
  for removing DBP precursors in many waters
• Moving the point of chlorination from raw water
  to settled or filtered water lowers DBP levels in
  finished water
• Coagulation and movement of the point of
  chlorination became best available technology
  (BAT) when DBPs were first regulated by USEPA in
  1979.
• In 1998, enhanced coagulation for the removal of
  DBP precursors (TOC) became part of the Stage 1
  Disinfectants/Disinfection By-Products Rule

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• Phil Singer (2)
• Ion Exchange for the Removal of Natural Organic
  Material
• Dissolved natural organic material is polyanionic
  in nature and should be readily removable from
  raw drinking water by anionic exchange.
• Removal of NOM prior to treatment should lower
  the coagulant demand, oxidant demand, and
  disinfection requirements for subsequent
  treatment of the water.

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Continuous-flow MIEX process
Contactors
Settler
Raw water
Treated water



Regeneration tank

1-15
85-99
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Freshly regenerated resin
Waste brine
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• Boyer, T.H. and P.C. Singer. Bench-Scale Testing
  of a Magnetic Ion Exchange Resin for Removal of
  Disinfection By-Product Precursors, Water
  Research, 39, 1265 (2005)
• Boyer, T.H. and P. C. Singer, A Pilot-Scale
  Evaluation of Magnetic Ion Exchange Treatment for
  Removal of Natural Organic Material and Inorganic
  Anions, Water Research, 40, 2865 (2006)
• Singer, P.C., M. Schneider, J. Edwards-Brandt,
  and G.C. Budd, Magnetic Ion Exchange for the
  Removal of Disinfection By-Product Precursors
  Pilot Plant Findings, Journ. Amer. Water Works
  Assoc., 99, 4, 128-139 (2007)

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Ion exchange stoichiometry

• Use NOM charge density to convert DOC from mg C/L
  to meq/L
• Net decrease in DOC and bicarbonate
  concentrations must equal net increase in
  chloride concentration

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Illustrative titration curves
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SRFA-bicarbonate-chloride exchange
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Fractional Degree of Resin Saturation
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USA and Australia
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Other Examples
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• Frederick George Pohland Medal Recipients
• The purpose of this award is to honor an
  individual who has made sustained and outstanding
  efforts to bridge environmental engineering
  research and practice.
• Award given annually by AEESP/AAEE
• Ray Loehr University of Texas
• Rhodes Trussell Trussell Environmental
  Consultants
• Herb Ward Rice University

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• Rhodes Trussell (1)
• Filtration
• Model of filter performance
• Used to design filter media of several large
  water treatment plants LA Aqueduct Filter Plant
  (600 mgd) and the Sydney Prospect WTP (900 mgd)
• Deep bed filter designs that evolved from this
  work have seen application around the world. 
  Originally mostly mono media, but in the past 20
  years, several deep bed dual media filters as
  well
• Use of extensive pilot studies looking at both
  time to breakthrough and time to limiting
  headloss over a range of media depths and/or
  sizes.

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• Rhodes Trussell (2)
• Air-stripping of VOCs
• Model for design of air strippers from first
  principles. 
• Have done a number of successful stripper designs
  using that model.
• Have used the model and pilot work to develop
  mass transfer coefficients for a number of
  packings.

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Rhodes Trussell (3) Advanced oxidation processes
(UV/O3, UV/H2O2, and O3/H2O2) based on hydroxyl
radical chemistry to remove PCE from groundwater
and MIB and Geosmin from surface
water Spreadsheet models of water chemistry to
predict pH changes due to air stripping, addition
of acids or bases construction of isopleths of
d(pH)/d(Alk) and d(pH)/d(CO2) to look at buffer
intensities Extensive use of disinfection
models to predict disinfection performance
dispersion and disinfection evaluations to
improve contactor performance
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• Ray Loehr
• Land application of wastes
• Bioavailability of hazardous chemicals and their
  associated risk

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Loehr (1) Land Application of Wastes Municipal
wastewater, animal waste, agricultural and
industrial wastewater, municipal sludge Prior to
1970, land application of wastes was based on
experience and empiricism often led to
groundwater contamination. Beginning in 1970s,
Cornell group attempted to developed an
environmentally sustainable approach to deal with
this practice. Applied chemical, biological,
hydrologic, and agronomic theory to land
application practices developed limiting
constituent concept. Developed a system of
appropriate application rates for various wastes
to applied to different types of soils. Used to
educate consulting engineers re dos and
donts. Their findings became the basis for EPA
design manuals and guidance documents for land
application of wastes.
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Loehr (2) Bioavailability and risk of hazardous
chemicals Mid-1990s realization that, at sites
requiring remediation, some biodegradable organic
chemicals were not readily degraded chemicals
did not appear to be available to the
MOs. Chemical extraction and subsequent analysis
could determine the quantity of chemicals
present, but could not determine their
availability or their risk. Sediment/water
partition coefficients can be used to determine
mobility and availability of contaminants.
Verified using real-world samples, but
partitioning in field samples tended to be quite
different from that in laboratory-spiked
samples. Subsequently developed a method using
mild supercritical carbon dioxide extraction to
determine chemical availability of hazardous
materials in real world soil and sediment samples
to assess their risk and inform site remediation
decisions.
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• Herb Ward
• Raymond Process for Aquifer Remediation
• Bioventing

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Raymond Process for Aquifer Remediation
THEORY Increase microbial degradation with
injection of H2O2 PRACTICE H2O2 addition
limited by microbial toxicity
(Fiorenza and Ward, 1997)
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Bioventing
THEORY Increase microbial degradation in vadose
zone with air injection PRACTICE Bioventing
now a presumptive remedy for LNAPL in vadose zone
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Bridging Theory and Practice Conclusions There is
a theoretical basis for what happens in
practice. If you understand the theory, you can
improve the practice. As engineers, practical
applications drive the theoretical research that
we do. Environmental engineering research has had
a major impact on environmental engineering
practice.
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Acknowledgments David Babcock, John Young, and
many other UNC students who worked on coagulation
of NOM for DBP precursor control Treavor Boyer -
UNC Ray Loehr University of Texas Rhodes
Trussell Trussell Environmental
Consultants Herb Ward Rice University